Bacteriophages as agents for the control of plant pathogenic bacteria - Disease Control in Crops - page 246

Chapter 13
Bacteriophages as agents for the control
of plant pathogenic bacteria

Botond Balogh 1,2 , Timur Momol 3 ,
Aleksa Obradovic 4 and Jeffrey Jones 1
1 University of Florida, Gainesville, FL 32611, USA
2 The Connecticut Agricultural Experiment Station, New Haven, CT 06504, USA
3 Plant Pathology Department, University of Florida, 1052 McCarty Hall, Gainsville,
FL 32611, USA
4 Faculty of Agriculture, University of Belgrade, 11080 Belgrade-Zemun, Serbia

13.1 Introduction - disease control for bacterial diseases

Diseases incited by bacterial plant pathogens are responsible for major economic losses
to agricultural production. Disease control is challenging for many diseases incited by
bacteria (Civerolo, 1982). The factors that contribute to those challenges are: (a) pathogen
variability, (b) high probability of overcoming plant genetic resistance and/or bactericide
sensitivity as a result of the high rate of mutation and gene transfer in the pathogen popu-
lation, (c) the pathogen's ability to reach high populations in a relatively short period of
time when conditions are conducive for disease development and (d) lack of effective
bactericides. For most plant diseases, including bacterial incited diseases, an integrated
management strategy is essential, combining proper cultural practices, biological control,
bactericides or plant activators, where applicable, and plant resistance (Obradovic et al. ,
2004, 2005).
Chemical control has been a signifi cant component of management strategies for con-
trolling plant diseases incited by bacteria. However, control with bactericides has been
extremely diffi cult because few effective bactericides are available. Copper has been used
more extensively than any other chemical for control of bacterial plant diseases; how-
ever, copper resistance is present in many plant pathogenic bacteria and is associated
with plasmid-borne and chromosomal resistance (Bender & Cooksey, 1986; Stall et al. ,
1986; Bender & Cooksey, 1987; Bender et al. , 1990; Lee et al. , 1994; Basim et al. , 1999;
Canteros, 1999). Antibiotics have also been used as part of a management strategy for
various bacterial diseases. Since the 1950s, the aminoglycoside antibiotic, streptomy-
cin, has been used (Thayer & Stall, 1961). As a result of extensive use, streptomycin-
resistant strains became prevalent, which resulted in reduced disease control effi cacy of
bacterial spot of tomato and pepper (Thayer & Stall, 1961), fi re blight of apple and pear
(Manulis et al., 1998), and many other bacterial plant pathogens (Cooksey, 1990). More
recently, systemic acquired resistance (SAR) plant inducers have been used and have
shown some success against bacterial diseases of tomato and pepper (Louws et al., 2001;